Gate valve

ABSTRACT

There is disclosed a gate valve having a non-rising stem which is adapted to form a metal-to-metal seal with the valve bonnet to contain pressure therein upon destruction of the primary, rubberlike stem seal.

iiite States Patent [191 [111 w Allen I ,Ean. 29, 1974 GATE VALVE [56]References Cited [75] inventor: Herbert Allen, Houston, Tex. UNITED ESAT TS Assigns: 333 11: Pg; Works, 3:23:23? 1311323 22fli???fiff?:.::::::1:11:11:332 i;3i

[22] Filed: Aug. 24, 1972 Primary Examiner-Martin? Schwadron [211 APPI-2835" 353:3, 52171 51753 33211 a].

[52] US. Cl 251/214, 251/266, 251125372764, [57] u ABSTRACT I I gg gg-3531 3; 3; g g $2f wfiiiI JZd iL 1121121254332532? with the valve bonnetto contain pressure therein upon destruction of the primary, rubber-likestem sea].

16 Claims, 7 Drawing Figures GATE VALVE This invention relates generallyto gate valves; and, more particularly, to improvements in gate valvesof the type having non-rising stems.

In a valve of this type, such as that shown and described on page 1 170of the 1970-71 issue of the Composite Catalog of Oil Field Equipment andServices, the stem is threadedly connected to the gate and is heldagainst axial movement by a thrust bearing in the bonnet, so thatrotation of the stem transmits axial force to the gate for moving itbetween positions opening and closing the valve. A seal member ofrubber-like material is carried in the bonnet toprovide a seal about thestem, and provision is also made for venting the interior of the bonnetoutwardly of the primary seal so as to prevent the build-up of excessivepressures within it. However, the high temperatures which may beencountered in the event of a tire near the valve may cause therubber-like material todeteriorate and thus permit line fluid to leakpast the stern and out of the valve.

Volpin US. Pat. No. 2,647,721 and Priese US. Pat. No. 3,177,887 showvalves in which an effort is made to anticipate this problem by means oftire seals wherein the stem has a shoulder arranged to engage a shoulderon the bonnet and thereby form a metal-tometal seal with the bonnet inthe event of such a tire or other cause for critically hightemperatures. More particularly, in each such valve, the stem shoulderis adapted to move into seating engagement with the bonnet shoulder uponfusion, at the destructive temperature level, of a part disposed betweenthem. However, in the Volpin patent, the closure member is a plug whichis fixed to the stem-so that it must rise with the stem to form the tireseal; and, in the Priese patent, the closure member is a ball which hasa tongue and groove connection with the stem so that the stem does not.

transmit axial force to the ball.

Thus, neither of these prior fire seal arrangements is suitable for agate valve having a non-rising stern, and it is therefore an object ofthis invention to provide a non-rising stem type of gate valve havingsuch a tire seal.

Another object is to provide a fire seal attachment which may be easilyadapted to existing gate valves of the type above described.

A further object is to provide a gate valve as defined in one or both ofthe foregoing objects in which pressure build-up within thebonnet isavoided, during normal use, by a vent which is adapted to be closed whenthe destructive temperatures occur.

Still another object is toprovide a gate valve as defined in theforegoing object wherein lubricant may be contained within the bonnetportion until such time as the fire seal is established.

These and other objects are accomplished, in accordance with theillustrated embodiments of the present invention, by a gate valve of thetype described in which the stem comprises inner and outer sections,with the inner section being threadedly connected to the gate and theouter section having a splined connection to the inner section to permitrelative axial move ment therebetween and extending outwardly of thebonnet to provide an exterior part to which rotation may be imparted. Abearing means is provided in the bonnet for holding the inner stemsection against axial movement, so that rotation of the stem causes thegate to move between opened and closed positions, and a primary sealmember of rubber-like material is carried by the bonnet for sealingabout the inner stem section, preferably beneath the bearing means, tocontain the line fluid and protect the bearing means against damage fromsuch fluid.

More particularly, there is an inwardly facing shoulder on the bore ofthe bonnet, and there is an outwardly facing shoulder on the outer stemsection which is adapted to be urged against the bonnet shoulder so asto close off the interior of the bonnet and thereby contain line fluidtherein upon destruction of the primary seal member due to excessivelyhigh temperatures. In certain embodiments of the invention, a means isprovided for venting the interior of the bonnet during normal use, andthen automatically closing the venting means in response to theexcessively high temperatures, whereby fluid is contained within thevalve despite destruction of the primary seal. In one such embodiment, ameans fusible in the presence of such temperatures is disposed betweenthe annular shoulders to space them apart. In another embodiment, thereis a port through the outer stern section, a closure for the port whichis urged toward port closing position, and a means for holding theclosure from closing position which is fusible in the presence of saidtemperatures to permit said closure to be urged to said port closing po'sition.

In still another embodiment of the invention, the bonnet is not normallyvented, and instead spring means are provided for urging the stemshoulder against the bonnet shoulder to form the metal-to-metal sealtherebetween. More particularly, in the preferred form of thisembodiment, the spring means acts between the stem section.

In the drawings, wherein the like reference characters are usedthroughout to designate like parts:

FIG. 1 is a vertical sectional view of a valve constructed in accordancewith the first-mentioned embodiment of the invention, and showing theshoulder on the outer stem section spaced from the shoulder on thebonnet so as to vent the interior of the bonnet;

FIG. 2 is an enlarged cross-sectional view of the bonnet of the valve inFIG. 1, as seen along broken line 2'2, and showing the fusible part forholding the shoulders spaced apart;

FIG. 3 is an enlarged vertical section of the upper end of the stem andbonnet of the valve of FIG. 1, but with the fusible part fused and thestern shoulder moved into seating engagement with the bonnet shoulder toclose the venting means;

FIG. 4 is a vertical sectional view of the upper end of the stem andbonnet of a valve constructed in accordance with the second-mentionedembodiment of the invention, and showing the closure thereof held by afusible part in a position spaced from the port through the upper stemsection to vent the interior of the bonnet;

FIG. 5 is a cross-sectional view of the stem and bonnet of FIG. 4, asseen along broken line 55 thereof;

FIG. 6 is a view similar to FIG. 4, but with the fusible part fused andthe closure moved to a position closing the port; and

FIG. 7 is a vertical cross-sectional view of the upper end of the stemand bonnet of a valve constructed in accordance with the third-mentionedembodiment of the invention.

With reference now to the above-described drawings, and particularly theembodiment of the invention shown in FIGS. 1 to 3, the overall valvewhich is shown in FIG. 1, and indicated in its entirety by referencecharacter 10, includes a valve body 11 having a flowway 12 therethroughand a chamber 13 therein intersecting the flowway and opening to the topside of the valve body. The valve also includes a bonnet 14 connected tothe topside of the valve body by bolts 15 and sealed with respectthereto by a seal ring 16. With the bonnet so connected to the valvebody, a bore 17 through it is aligned with the open end of the chamber13.

A gate 18 having a port 19 therein is slidable vertically within thechamber between a position in which the port is aligned with the flowway12 to open the valve, as shown in FIG. 1, and in which the port isbeneath the flowway so as to close the valve. Retainer plates 18A arecarried within the chamber 13 on opposite sides of the chamber.

A stem 20 rotatably mounted in the bore 17 of the bonnet includes aninner section 21 threadedly connected to gate 18 at 22 and an outersection 23 having a spline connection 24 to the inner section to form anextension thereof. The upper end of the upper stem section 23 extendsthrough a hole 25 in the upper end of the bonnet to provide an exteriorpart 26 to which rotation may be imparted. Thus, with the inner stemsection 21 held against axial movement in the bonnet, rotation of thestem extension will cause the gate to move vertically between flowwayopening and closing positions.

As shown in FIG. 1, the lower stem section 21 is so held by means ofroller bearings 27 and 31 on the upper and lower sides of a flange 29 onits upper end. The flange is releasably connected to the main portion ofsuch stern section by a pin 30 and has an upper extension which forms afemale portion of the spline 24. The upper bearings 27 are held down onthe flange by a downwardly facing shoulder 28 on the bore of the bonnet,and the flange in turn holds the lower bearings 31 down on an upwardlyfacing shoulder 28A of the bonnet.

Bonnet 14 comprises a lower or base portion 32 having a flange throughwhich the bolts 14 extend, a cap 33 threadedly connected at 34 to anupward extension from the flange of the bonnet section 32 and a nut 36threadedly connected at 37 to the interior of the base portion.Shoulders 28 and 28A are formed on the cap 33 and nut 36, respectively,so that upon making up of the threads between the cap and the bonnetsection 32, flange 29 on stem section 21 is held tightly between thebearings 27 and 31.

A seal member of rubber-like material is held down within the bore ofthe bonnet section 32 by the nut 36 to provide a primary seal about thelower stem section 21. A shoulder 38 is formed on the inner diameter ofthe cap 33 above its threads 34 for bearing on the upper side of the nut36 when both the nut and the cap are threadedly connected to the bonnetsection 32. Thus, a seal is formed between shoulder 38 and the nutbetween the nut and the upper end of the upwardly extending portion ofthe bonnet section 32 to prevent leakage of line fluid from the interiorof the bonnet through the threaded connection 34.

An inwardly or downwardly facing annular shoulder 40 is formed in thebore of the upper end of the cap 33, and a complementary outwardly orupwardly facing annular shoulder. 41 is formed on the upper stem section23 above the spline connection 24. In normal use of the valve, the upperstem section 23 is supported in the position of FIG. 1, in which itsshoulder is beneath the bonnet shoulder, by means of a split ring 43about the upper stem section for seating on the upper end of the bonnet.The stem shoulder is held spaced from the bonnet shoulder by means of aring 42 disposed between them and formed of a relatively low meltingpoint material, such as solder or plastic, which is relatively rigid ascompared with rubber, but fusible at elevated temperatures which woulddestroy the rubberlike material of the seal member 35. Thus, aspreviously described, upon loss of the primary seal, ring 42 will fuseto permit the upper stem section to move upwardly to seat against thebonnet and thus form a metal-tometal seal therewith to close theinterior of the bonnet. That is, as shown, the upper stern section fitsrelatively closely within the bore of the bonnet beneath the fusiblering, so that pressure will be effective to urge it upwardly.

As best shown in FIG. 2, the ring 42 is discontinuous so that theinterior of the bonnet is vented to the atmosphere trough the hole 25 inthe upper end of the bonnet during normal use of the valve. However,upon fusing of the ring, the metal-to-metal seal between shoulders 40and 41 closes off the interior of the bonnet to prevent loss of linefluid from the bonnet upon destruction of the primary seal 35.

As best shown in FIG. 3, an O-ring 44 is carried in a groove about theupper stem section above bonnet shoulder 41 and beneath the split ring43. More particularly, this groove is formed in a cylindrical portion ofthe outer diameter of the upper stem section which fits relativelyclosely within the hole 25 through the upper end of the bonnet when thestern section is in its lower postion of FIG. 1. Thus, in this latterposition of the stem section, the ring 44 engages the hole 25 withrelatively light pressure which is sufficient to contain lubricantwithin the bonnet, but insufficient to contain fluid under highpressure. Thus, while containing lubricant, seal ring 44 does notprevent the high pressure fluids from venting.

The second embodiment of the valve of the present invention is identicalto that of FIGS. 1 to 3 except with respect to the portions of the upperends of its bonnet and stem illustrated in FIGS. 4 to 6. Thus, aninwardly facing annular shoulder 40A is formed on a ring 51 of bronze orother bearing material held in the upper end of the cap just beneathhole 25A therein. An upwardly facing annular shoulder 41A on an upperstern section 23A is urged into seating engagement with shoulder 40A ina manner to be described, so that the shoulders provide a metal-to-metalseal between the uper ends of the stem and bonnet, during use of thevalve, both prior to and following destruction of the primary stem seal.

The upper stem section 23A is provided with a longitudinal bore 45connecting with a port 46 leading to its upper end. A conical seat 47 isprovided at the intersection of the stem bore and port, and aball-shaped closure 48 is disposed within the stern bore for movementbetween a position opening the port to vent the interior of the bonnetto atmosphere, as shown in FIG. 4, and a position closing the port toclose the vent, as shown in FIG. 6. Although the closure 48 is urgedupwardly toward closed position by means of a coil spring 50 disposedbetween its lower side and the upper end of lower stem section 21A, itis held in open position, during normal use of the valve, by means of apin 49 extending across the bore beneath the seat 47. This pin is madeof a fusible material similar to that of ring 42 of the first-describedembodiment, so as to be fusible at the elevated temperature whichdestroys the primary seal, thus permitting the closure to be urgedupwardly by spring 50 into metal-to-metal sealing engagement with theseat 47 to close port 46 and the interior of the bonnet.

The valve constructed in accordance with the thirdmentioned embodimentof the invention is also substantially identical to the valve of thefirst-mentioned embodiment, with the exception of the portions of theupper ends of its bonnet and stem illustrated in FIG. 7. Thus, aninwardly facing annular shoulder 40B is formed in the bore of the capbeneath a hole 25B therethrough in position to be engaged by acomplementary annular shoulder 41B about an upper stem section 23B. Asin the case of the second embodiment of the invention, the stem shoulderis urged upwardly into seating engagement with the shoulder 408 so as toprovide a metal-to-metal seal between the stem and bonnet during use ofthe valve both prior. to and following destruction of the primary seal.For this purpose, a spring washer is disposed between a flange 298 on alower stem section 21B and the lower end of the upper stem section 23B.A spline'connection 24B is formed between the upper and lower stemsections 238 and 218. Although this embodiment provides no means forventing the interior of the bonnet during normal use of the valve, anexterior part 268 of the upper stem section 23B maybe depressed ifdesired to periodically relieve excessive pressure within the bonnet.

From the foregoing it will be seen that this invention is one welladapted to attain all of the ends and objects hereinabove set forth,together with other advantages which are obvious and which are inherentto the apparatus.

It will be understood that certain features and subcombinations are ofutility andmay be employed without reference to other features andsubcombinations.

This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the invention withoutdeparting from the scope thereof, it is to be understood that all matterherein set forth or shown in the accompanying drawings is to beinterpreted as illustrative and not in a limiting sense.

The invention having been described, what is claimed l. A gate valve,comprising a valve body having a flowway therethrough and a chambertherein intersecting the flowway and opening to one side of the valvebody, a bonnet sealably connected to the valve body and having a boretherethrough aligned with the chamber opening, a gate slidable withinthe chamber between positions opening and closing the flowway, a stemrotatably mounted in the bore of the bonnet, said stem including aninner section threadedly connected to the gate and an outer sectionhaving a spline connection to the inner section to permit relative axialmovement therebetween and extending through the outer end of the bonnetbore to provide an exterior part to which rotation may be imparted, aseal member of rubber-like material in the bonnet for sealing about theinner stem section, bearing means in the bonnet for holding the innerstem section against axial movement so that rotation of said stem causesthe gate to move between flowway openingand closing positions, aninwardly facing annular shoulder on the bonnet bore, and an outwardlyfacing annular shoulder on the outer stem section for forming ametal-to-metal seal with the bonnet shoulder to close off the interiorof said bonnet whereby fluid is contained therein in the event said sealmember is destroyed.

2. A valve of the character defined in claim 1, including means forventing the interior of said bonnet, and means for closing said ventingmeans in response to a temperature at which said seal member isdestroyed.

3. A valve of the character defined in claim 2, wherein said ventingmeans comprises means disposed between said annular shoulders and beingfusible in the presence of said temperature to permit the stem sectionshoulder to move into engagement with the bonnet shoulder.

4. A valve of the character defined in claim 3, including a seal ringcarried by the outer stem section for engaging obe bonnet bore at itsouter end so as to contain lubricant in the bonnet prior to fusing ofsaid spacing means.

5. A valve of the character defined in claim 2, wherein said ventingmeans comprises means providing a port through the outer stem section, aclosure for the port and urged toward port closing position, and meansholding the closure away from port closing position and being fusible inthe presence of said temperature to permit said closure to be urged toport closing position.

6. A valve of the character defined in claim 1, including spring meansengaging the outer stem section to urge its shoulder against the bonnetshoulder.

7. A valve of the character defined in claim 6, wherein the spring meansacts between the stem sections.

8. A valve of the character defined in claim 1, wherein said bonnetincludes a base portion and a cap connected to the base portion, saidseal member being carried in and said inner stem section being supportedon the base section, said cap having means for holding the inner sternsection down, and said bonnet shoulder being formed on the cap outwardlyof the holding means.

9. A fire seal attachment for a gate valve having a bonnet base portion,a non-rising stem section having an outer end extending through the baseportion, a spline on the outer end of the non-rising stem section, and aseal member of rubber-like material carried within the bonnet to sealabout the non-rising stem section, said attachment comprising a caphaving a hole in one end and means at the other end of connection to thebase portion in surrounding relation to the outer end of the non-risingstem section, another stem section having an inner end with a spline forconnection to the spline on the non-rising stem seetion'to permitrelative axial movement therebetween and an outer end which extendsthrough the hole in the cap, an inwardly facing annular shoulder on thecap, and an outwardly facing annular shoulder on the other stern sectionfor forming a metal-to-metal seal with the cap shoulder 'to close offthe .interior of the bonnet,

whereby fluid is contained therein in the event said seal member isdestroyed.

10. An attachment of the character, defined in claim 9, including meansdisposed between said annular shoulders and being fusible in thepresence of a temperature at which said seal member is destroyed.

11. An attachment of the character defined in claim 9, including meansproviding a port through said other stem section, a closure for the portadapted to be urged to port closing position, and means holding theclosure away from port closing position and being fusible in thepresence of a temperature at which said seal member is destroyed.

12. An attachment of the character, as defined in claim 9, including aspring disposable between the nonrising stem section and the other stemsection to urge said stem shoulder against said cap shoulder.

13. A fire seal attachment for a gate valve having a bonnet baseportion, a stem section having an outer end extending through the baseportion, and a seal member of rubber-like material carried within thebonnet to seal about the stem section, said attachment comprising abearing part eonnectable to the outer end of the stern section, a splineon the bearing part, a cap having means at one end for connection to thebase portion in surrounding relation to the outer end of the non-risingstem section and a hole in the other end, means on the cap for holdingthe bearing part against the bonnet portion to prevent axial movement ofsaid stem section, another stem section having an inner end with aspline for connection to the spline on the bearing part to permitrelative axial movement therebetween and an outer end which extendsthrough the hole in the cap, an inwardly facing annular shoulder on thecap, and an outwardly facing annular shoulder on the other stem sectionfor forming a metal-to-metal seal with the cap shoulder to close off theinterior of the bonnet, whereby fluid is contained therein in the eventsaid seal member is destroyed.

14. An attachment of the character defined in claim 13, including meansdisposed between said annular shoulders and being fusible in thepresence ofa temperature at which said seal member is destroyed.

15. An attachment of the character, defined in claim 13, including meansproviding a port through said other stern section, a closure for theport adapted to be urged to port closing position, and means holding theclosure away from port closing position and being fusible in thepresence of a temperature at which said seal member is destroyed.

16. An attachment of the character, defined in claim 13, including aspring disposable between the bearing part and the other stem section tourge said stem shoulder against said cap shoulder.

1. A gate valve, comprising a valve body having a flowway therethroughand a chamber therein intersecting the flowway and opening to one sideof the valve body, a bonnet sealably connected to the valve body andhaving a bore therethrough aligned with the chamber opening, a gateslidable within the chamber between positions opening and closing theflowway, a stem rotatably mounted in the bore of the bonnet, said stemincluding an inner section threadedly connected to the gate and an outersection having a spline connection to the inner section to permitrelative axial movement therebetween and extending through the outer endof the bonnet bore to provide an exterior part to which rotation may beimparted, a seal member of rubber-like material in the bonnet forsealing about the inner stem section, bearing means in the bonnet forholding the inner stem section against axial movement so that rotationof said stem causes the gate to move between flowway opening and closingpositions, an inwardly facing annular shoulder on the bonnet bore, andan outwardly facing annular shoulder on the outer stem section forforming a metal-to-metal seal with the bonnet shoulder to close off theinterior of said bonnet whereby fluid is contained therein in the eventsaid seal member is destroyed.
 2. A valve of the character defined inclaim 1, including means for venting the interior of said bonnet, andmeans for closing said venting means in response to a temperature atwhich said seal member is destroyed.
 3. A valve of the character definedin claim 2, wherein said venting means comprises means disposed betweensaid annular shoulders and being fusible in the presence of saidtemperature to permit the stem section shoulder to move into engagementwith the bonnet shoulder.
 4. A valve of the character defined in claim3, including a seal ring carried by the outer stem section for engagingobe bonnet bore at its outer end so as to contain lubricant in thebonnet prior to fusing of said spacing means.
 5. A valve of thecharacter defined in claim 2, wherein said venting means comprises meansproviding a port through the outer stem section, a closure for the portand urged toward port closing position, and means holding the closureaway from port closing position and being fusible in the presence ofsaid temperature to permit said closure to be urged to port closingposition.
 6. A valve of the character defined in claim 1, includingspring means engaging the outer stem section to urge its shoulderagainst the bonnet shoulder.
 7. A valve of the character defined inclaim 6, wherein the spring means acts between the stem sections.
 8. Avalve of the character defined in claim 1, wherein said bonnet includesa base portion and a cap connected to the base portion, said seal memberbeing carried in and said inner stem section being supported on the basesection, said cap having means for holding the inner stem section down,and said bonnet shoulder being formed on the cap outwardly of theholding means.
 9. A fire seal attachment for a gate valve having abonnet base portion, a non-rising stem section having an outer endextending through the base portion, a spline on the outer end of thenon-rising stem section, and a seal member of rubber-like materialcarried within the bonnet to seal about the non-rising stem section,said attachment comprising a cap having a hole in one end and means atthe other end of connection to the base portion in surrounding relationto the outer end of the non-rising stem section, another stem sectionhaving an inner end with a spline for connection to the spline on thenon-rising stem section to permit relative axial movement therebetweenand an outer end which extends through the hole in the cap, an inwardlyfacing annular shoulder on the cap, and an outwardly facing annularshoulder on the other stem section for forming a metal-to-metal sealwith the cap shoulder to close off the interior of the bonnet, wherebyfluid is contained therein in the event said seal member is destroyed.10. An attachment of the character, defined in claim 9, including meansdisposed between said annular shoulders and being fusible in thepresence of a temperature at which said seal member is destroyed.
 11. Anattachment of the character defined in claim 9, including meansproviding a port through said other stem section, a closure for the portadapted to be urged to port closing position, and means holding theclosure away from port closing position and being fusible in thepresence of a temperature at which said seal member is destroyed.
 12. Anattachment of the character, as defined in claim 9, including a springdisposable between the non-rising stem section and the other stemsection to urge said stem shoulder against said cap shoulder.
 13. A fireseal attachment for a gate valve having a bonnet base portion, a stemsection having an outer end extending through the base portion, and aseal member of rubber-like material carried within the bonnet to sealabout the stem section, said attachment comprising a bearing partconnectable to the outer end of the stem section, a spline on thebearing part, a cap having means at one end for connection to the baseportion in surrounding relation to the outer end of the non-rising stemsection and a hole in the other end, means on the cap for holding thebearing part against the bonnet portion to prevent axial movement ofsaid stem section, another stem section having an inner end with aspline for connection to the spline on the bearing part to permitrelative axial movement therebetween and an outer end which extendsthrough the hole in the cap, an inwardly facing annular shoulder on thecap, and an outwardly facing annular shoulder on the other stem sectionfor forming a metal-to-metal seal with the cap shoulder to close off theinterior of the bonnet, whereby fluid is contained therein in the eventsaid seal member is destroyed.
 14. An attachment of the characterdefined in claim 13, including means disposed between said annularshoulders and being fusible in the presence of a temperature at whichsaid seal member is destroyed.
 15. An attachment of the character,defined in claim 13, including means providing a port through said otherstem section, a closure for the port adapted to be urged to port closingposition, and means holding the closure away from port closing positionand being fusible in the presence of a temperature at which said sealmember is destroyed.
 16. An attachment of the character, defined inclaim 13, including a spring disposable between the bearing part and theother stem section to urge said stem shoulder against said cap shoulder.